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Biomedical subjects

I W Fellows

Publications and source records attributed to I W Fellows.

At least 37 records · Page 2Linked to original sources
PubMed1988

Metabolic and cardiovascular effects of infusions of low doses of isoprenaline in man.

1. The cardiovascular and metabolic responses to low doses of isoprenaline (15 and 5 ng min-1 kg-1 body weight infused over 30 min) were determined in six healthy males. The study was performed to investigate whether there were sustained effects after the termination of the isoprenaline infusion, as has been observed previously after the infusion of adrenaline. 2. The isoprenaline infusions produced dose-dependent increases in heart rate, systolic blood pressure and metabolic rate, but similar increases in calf blood flow and decreases in diastolic blood pressure for the two infusion rates. Finger tremor was increased in amplitude by the 15 ng min-1 kg-1 infusion only. The changes in each of these physiological variables largely resolved within a few minutes of discontinuing the isoprenaline infusions. 3. There were no changes in arterialized venous plasma adrenaline or noradrenaline levels during the isoprenaline infusions. Mean peak plasma isoprenaline levels were 0.16 +/- 0.02 nmol/l during the 5 ng min-1 kg-1 infusion and 0.71 +/- 0.05 nmol/l during the 15 ng min-1 kg-1 infusion. 4. Plasma insulin levels increased with isoprenaline but blood glucose concentrations were unchanged, consistent with a direct effect of isoprenaline on beta 2-adrenoceptors mediating insulin release from pancreatic beta-cells. Blood glycerol concentration also increased with isoprenaline but blood lactate concentration was unaltered. 5. The present study demonstrates pronounced cardiovascular and metabolic effects of low dose isoprenaline infusions. Differences in the rate of resolution of the changes induced by isoprenaline and by adrenaline seen in previous studies may result from a significant difference in their metabolism.

Adult↗
PubMed1988

Effect of intravenous infusion of adrenaline on the cardiovascular responses to distal body subatmospheric pressure in man.

1. On two separate occasions, at least 1 week apart, seven young healthy male subjects received intravenous infusions of either adrenaline [0.27 nmol (50 ng) min-1 kg-1] or saline (154 mmol/l NaCl), plus ascorbic acid (5.68 mmol/l), over 30 min. 2. On each occasion, the subjects were exposed to distal body subatmospheric pressure (DBSP), 0 to 50 mmHg (0 to 6.65 kPa) in 10 mmHg (1.33 kPa) steps, before infusion, during the final 15 min of the infusion, and at 15 min and 30 min after the cessation of the infusion. 3. Venous adrenaline concentrations of 2.85 +/- 0.22 nmol/l were achieved during the adrenaline infusion, compared with 0.49 +/- 0.07 nmol/l during the saline infusion (P less than 0.001). At 15 min and at 30 min after cessation of the adrenaline infusion, venous adrenaline concentrations had fallen to levels similar to those achieved after the cessation of the saline infusion. 4. Heart rate rose significantly from 58 +/- 4 beats/min to 67 +/- 4 beats/min during the adrenaline infusion (P less than 0.05), but there was no further significant change in response to 50 mmHg (6.65 kPa) DBSP. At 30 min after the cessation of the adrenaline infusion, heart rate rose from 60 +/- 4 beats/min to 78 +/- 7 beats/min in response to 50 mmHg DBSP. This increase was significantly greater than that observed before the adrenaline infusion [58 +/- 4 beats/min to 69 +/- 7 beats/min during 50 mmHg (6.65 kPa) DBSP; P less than 0.01].(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Trends in splenectomy in the Trent region 1972-85.

During the period 1972-85, 3712 splenectomies were performed in the Trent region giving a mean splenectomy rate of 5.8 per 100,000 population per year. Of these, 37.4% were incidental to other surgical operations and 23.4% were as a result of trauma. During this period there was a marked reduction in the splenectomy rate in children aged under 10 years for trauma and for haematological diseases. No such reduction was observed in older patients for these indications. Splenectomy for lymphoma fell progressively after 1977.

Age Factors↗
PubMed1988

Choice of therapy for achalasia in relation to age.

Over an 11-year period 132 patients with achalasia underwent a total of 253 pneumatic bag dilatations of the cardia as the initial treatment. Adequate symptomatic relief was obtained in the majority, but 16 needed cardiomyotomy after pneumatic dilatation had failed to give lasting symptomatic relief. Older patients, aged 60 years or more, showed longer-lasting improvement with pneumatic dilatation than did younger ones and only 1 patient over 50 required cardiomyotomy. Benefit from pneumatic dilatation showed a closer relationship to age than to oesophageal diameter. Of 50 patients followed for more than 5 years, 48% required no further treatment, 40% needed at least one further dilatation to achieve symptomatic relief and 12% came to cardiomyotomy. This study suggests that pneumatic dilatation is safe, effective and particularly useful in the management of the elderly achalasic patient.

Adolescent↗
PubMed1988

Crohn's disease in West Indians.

An epidemiological survey in the City of Derby from 1976 to 1985 indicated that there was no significant difference in the incidence of Crohn's disease in West Indians (4.5-5.6/10(5)/yr) and the caucasian population (7.0/10(5)/yr). These results indicate that West Indians are not genetically protected against the development of Crohn's disease.

Adolescent↗
PubMed1987

The effect of insulin-induced hypoglycaemia on gastrointestinal motility in man.

The effect of insulin-induced hypoglycaemia on gastro-jejunal motility was studied in five, healthy, male subjects using tethered, pressure sensitive, radiotelemetry capsules. Thirty minutes after the intravenous injection of soluble insulin (0.15 unit/kg body weight), a significant reduction in blood glucose concentration (control: 5.26 +/- 0.19 SEM mmol/l; insulin: 1.48 +/- 0.44 mmol/l; P less than 0.001) was associated with a rise in heart rate (mean peak rise 29 +/- 8 beats/min, P less than 0.05), systolic arterial blood pressure (mean peak rise 28 +/- 4 mmHg, P less than 0.01) and plasma pancreatic polypeptide concentration (control: 20 +/- 7 pmol/l; insulin: 287 +/- 66 pmol/l; P less than 0.01). These events coincided with a short period of jejunal motor activity, which was not associated with gastric motor activity nor with raised plasma motilin concentrations. During the control study, there were no changes in blood glucose concentration, heart rate, arterial blood pressure or plasma pancreatic polypeptide concentrations, and there was no jejunal motor activity. The interval between successive gastric migrating motor complexes (MMC) was not significantly different in the insulin and control studies (control: median interval 110 min, range 108-148 min; insulin: median interval 124 min, range 115-125 min), suggesting that the fasting gastrojejunal MMC and jejunal motor activity arose independently. Insulin-induced hypoglycaemia is accompanied by jejunal motor activity, which may underlie the abdominal symptoms associated with hypoglycaemia.

Adult↗
PubMed1987

[14C]-triolein absorption: a useful test in the diagnosis of malabsorption.

The [14C]-triolein absorption test has been assessed using a preprepared fat meal in a procedure that can be completed within a working day on an inpatient or outpatient basis. An initial study showed complete discrimination between 30 control subjects and 13 patients with raised faecal fat excretion. A prospective evaluation in 57 patients under investigation for gastrointestinal disease showed a sensitivity of 85% and specificity of 93% (100% if two obese subjects are excluded). The test discriminates satisfactorily between patients with and without fat malabsorption and makes the measurement of faecal fat unnecessary in most circumstances.

Adult↗
PubMed1986

Low plasma concentrations of adrenaline and physiological tremor in man.

Finger tremor was measured in six normal subjects during intravenous infusions of adrenaline (10 ngkg-1min-1 and 50 ngkg-1min-1) resulting in venous plasma adrenaline concentrations within the physiological range (0.77 +/- 0.08 and 2.28 +/- 0.18 nmoll-1). Tremor amplitude significantly increased after 15 and 25 minutes infusion at the higher dose of adrenaline. The lower dose of adrenaline increased tremor in three of the six subjects.

Adult↗
PubMed1986

Celestin dilatation of benign esophageal strictures: a review of 100 patients.

Over the last 4 yr 302 Celestin dilatations have been performed in 100 patients with benign esophageal strictures. Patients presenting with tighter strictures have a significantly increased need for subsequent dilatation (p less than 0.001). The technique described permits rapid turnover of patients in the endoscopy suite and may be used in even the most elderly patients.

Aged↗
PubMed1985

The effect of adrenaline upon cardiovascular and metabolic functions in man.

On three separate occasions, at least 1 week apart, seven young healthy male subjects received intravenous infusions of either adrenaline, 50 ng min-1 kg-1 (high A), adrenaline, 10 ng min-1 kg-1 (low A) or sodium chloride solution (saline: 154 mmol of NaCl/l) plus ascorbic acid, 1 mg/ml (control), over 30 min. Venous adrenaline concentrations of 2.19 +/- 0.15 nmol/l, 0.73 +/- 0.08 nmol/l and 0.15 +/- 0.03 nmol/l were achieved during the high A, low A and control infusions respectively. Heart rate rose significantly by 19 +/- 3 beats/min (high A) and by 6 +/- 1 beats/min (low A). Heart rate remained significantly elevated 30 min after cessation of the high A infusion, despite venous plasma adrenaline concentration having fallen to control levels. The diastolic blood pressure fell during the high A and low A infusions, but the systolic blood pressure rose only during the high A infusion. Vasodilatation occurred in the calf vascular bed during both high A and low A infusions. The changes in hand blood flow and hand vascular resistance were not statistically significant, although there was a tendency to vasoconstriction during the infusion of adrenaline. Metabolic rate rose significantly by 23.5 +/- 1.8% (high A) and by 11.8 +/- 1.6% (low A). Metabolic rate remained elevated between 15 and 30 min after termination of the high A infusion. There was an initial transient increase in respiratory exchange ratio (RER) during the adrenaline infusions. During the later stages of the adrenaline infusions and after their cessation, RER fell, probably reflecting increased fat oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

The effect of undernutrition on thermoregulation in the elderly.

With use of a liquid-conditioned coverall, the thermoregulatory responses to a lowering of environmental temperature from 35 degrees C to 23 degrees C were assessed in eight normally nourished and six undernourished elderly female patients, during their convalescence after surgical repair of a fracture of the femoral neck. There was no difference in the peripheral vasoconstriction of the two groups in response to a cold environment. On lowering the environmental temperature, the increase in metabolic rate was significantly impaired in the undernourished group compared with the normally nourished group (P less than 0.05). There was a small decrease in core temperature in the undernourished group (median change -0.1 degree C) during the period of exposure to the lowest environmental temperature (23 degrees C). This was significantly different from the lack of change (median change 0 degrees C) in core temperature observed in the normally nourished group (P less than 0.05). This defect of thermogenesis may underlie the propensity of undernourished elderly patients to suffer hypothermia and fracture of the femoral neck in the winter months.

Aged↗